The present invention relates to an agricultural and horticultural fungicide and fruit storage disease preventing composition and a process for production thereof.
Heretofore, heavy metal compounds such as copper, mercury or arsenic compounds, organic chlorine compounds, and organic phosphoric acid compounds have widely been used as fungicide, but these chemicals are harmful to the human body and animals, contaminate the soil and thus pose a serious problem in connection with environmental pollution.
Under such circumstances, there has been a pressing need for a safe agricultural and horticultural fungicide which has no ill-effects on humans body and animals.
In fact, however, no satisfactorily safe fungicide has yet been found for use with garden products and fruit trees, especially for use with vegitables and fruits which are merely washed with water before eating.
In view of such state of the art, the inventors of the invention carried out an extensive study on the development of highly safe and effective drugs for plant diseases and have found that sodium bicarbonate has a high fungicidal effect on plant diseases. This discovery led to the accomplishment of the present agricultural and horticultural fungicide which contains sodium bicarbonate as one effective component.
Although sodium bicarbonate is a very well-known and wery safe compound which is widely used as a medicaments and in food blowing agents such as baking powder, its fungicidal effect has not heretofore been known.
Sodium bicarbonate cannot, however, be used alone as a fungicide because it is inferior in adhesiveness and spreadability. Moreover, in a liquid form such as aqueous solution, it has a high surface tension and does not attach to the plant body well enough to manifest satisfactory fungicidity.
Accordingly, the inventors considered combined use of sodium bicarbonate with a surfactant and as a result of this study they found that there are certain limitations on the surfactants that can be used with sodium bicarbonate. These limitations derive from the fact that sodium bicarbonate exhibits alkaline behavior in an aqueous solution and, because of this, exhibits poor compatability with some surfactants.
In spite of the difficulty in finding suitable surfactants, the inventors continued their study because they were well aware of the tremendous advantages to be obtained if sodium bicarbonate could be used as a fungicide on vegetables or fruits. Their study eventually resulted in the development of a non-polluting fungicide comprising sodium bicarbonate in combination with food emulsifiers used as the surfactants.
It was found that food emulsifiers themselves exhibit fungicidal effect, albeit weakly. When a food emulsifier is used together with sodium bicarbonate, the two chemicals show excellent compatibility. Moreover, the composition is easy to apply to plants and displays not only good adhesiveness but also a synergistic fungicidal action resulting in a control effect over 90% against etiological cause of a plant diseases and fruit storage diseases.